An information processing apparatus such as a notebook-sized personal computer apparatus uses a position input apparatus including a conventional position detecting apparatus to detect the position touched by a user's finger. This conventional position detecting apparatus includes a plurality of electrodes embedded in an operation surface to detect the user's finger by determining changes in electrostatic capacity between the electrodes that occur when the user's finger touches the operation surface.
In the notebook-sized personal computer apparatus, a position of a pointer displayed in a display portion changes in response to a change in the position of the user's finger with respect to the operation surface of the conventional position detecting apparatus. In order to detect the change in the electrostatic capacity between the electrodes with stability, the position detecting apparatus is typically provided with a conductor plate disposed below the electrode(s). This conductor plate is used to ground the conventional position detecting apparatus as an earth ground electrode.
Many small and portable electronic apparatuses such as the notebook-sized personal computer apparatus (described above) use the conventional position detecting apparatus described above. Since the conventional position detecting apparatus includes the conductor plate in the portable apparatus to provide a ground electric potential portion, a problem arises in that other electronic components/devices cannot be disposed under/near the conductor plate. This is due to the fact that an eddy current is induced in the conductor plate by an alternating field of the electrodes of the conventional position detecting apparatus. This eddy current affects operations of the portable electronic apparatuses and would affect any other electronic components/devices disposed near the conductor plate.
For this reason, it is difficult to position other electronic components/devices below or near the conductor plate. As a result, a problem arises in that the space under the conductor plate cannot be utilized effectively and there is a limited amount of space in which to arrange the other electronic components/devices of the portable electronic apparatuses.